Engine



Sept. 6, 1932.

R. LEE

ENGINE Filed Nov. 25, 1929 MEW 45 radial and axial thrust.

Patented Sept. 69 1932 ROYAL LEE, QF MILWAUKEE, WISCONSIN, ASSIGNOR TLEE ENGINEERING RESEARCH CORPORATION, OF MILWAUKEE, WISCONSIN, ACORPORATIN OF WISCONSIN ENGINE j Application led November 25, 1929.Serial No. 409,583.

The invention relates to engines, and more particularly to enginesadapted for the driving of propellers. f

Anobject of the invention is to provide an engine including a rotarypower shaft and a piston-receiving power cylinder therefor which isarranged longitudinally of the shaft, whereby to reduce the radialdimensions of the engine in order to facilitate stream-lining and toexpedite the mounting of the engine on narrow bodies such as aeroplanefu selages and wings.

Another object is to provide an engine of this type in which the shaftspeed is a submultiple of the piston frequency.

A further object of the invention is to provide an engine includingco-aXial driving shafts which rotate in opposite directions toneutralize torque eects and to minimize gyroscopic effects.

A further object is tprovide drivingl means for the shafts including apairof reciprocablepistons moving in opposite directions. I

A further object is to provide an engine of this type inclu-ding cammeans for effecting the opposite rotation of the shafts.

The invention further consists in the several features hereinafter setforth and more particularly defined by the annexed claims.

In the accompanying drawing, Fig. 1 is a longitudinal sectionalelevation of an engine embodying the invention; l

l u n l i Flg. 2 1s a detall view of an inner cam l drum forming part ofthe engine, and

Fig. 3 is a sectional detail view of an outer cam drum forming part ofthe engine.

In this drawing, the numeral- 10 desi nates a tubular casing in which ahollow sha "m 11 is jlournalled by means of bearings 12 adapted to takeboth radial and axial thrust. A shaft 13 is disposed co-axially withinthe hollow shaft 11 and is journalled therein by means of bearings 14adapted to take both The shafts 11 and 13 project beyond the end of thecasing 10, and the inner sha-ft 13 also projects beyond the end of theouter shaft 11. A propeller 15 is xedly secured tothe outer shaft 11,and a propeller 16 is xedly secured to the inner shaft 13, thepropellers 15 and 16 being arranged in tandem relation. In the presentinstance, the propellers 15 and 16 are indicated to be air screws.

A cylindrical cam drum 17 is mounted on the inner end of the hollowshaft 11 and a similar but smaller cam drum 18 within the cam drum 17 ismornted on the shaft 13. The cam drums 17 and 18 are providedrespectivelyl in their adjacent surfaces with cam grooves or channels 19and 20 of substantially sinusoidal shape and having the same amplitude,there being two pairs of vertices in each groove.

An engine cylinder 21 is arranged co-axially of the concentric shafts 11and 13 and inspaced relation to the cam drums, the cylinder including anoutwardly flanged portion which is rigidly secured to the casin 10. Apair of pistons 22 and 23 are slidab y mounted in. the cylinder 21 forreciprocation in opposite directions and are provided with respectivepiston pins 24 and 25 extending through slots 26 in the cylinder walls.The piston pin 24 is secured at its end portions to a pair o connectingrods 27 arranged in parallel relation to the axis of the cylinder andhaving their forward portions extendin between thel cam drums 17 and 18where t ey are each. prc. vided with aligned rollers 28 entering the camgrooves 19 and 20 in the cam drums to engage the side walls of thesegrooves. The

4piston pin 25 is similarly secured at its end portions to a pair ofconnecting rods 29 arranged in parallel relation to the axis of thecylinder and having theirv forward portions extending between the camdrums 17 and 18 where they are each provided with rollers 30 enteringthe cam grooves 19 and 20 in the cam drums to engage the side walls ofthese grooves. The piston pins 24 and 25 are arranged at right-angles toeach other and thel connecting rods 27 and 29 are correspondinglyarranged in planes at right-,angles to each other, the rollers 28 and 30on 4the connecting rods being spaced 90 apart on the cam drums. Theconnecting rods 27 may be rigidly connected together, as by means of across bar 31, and the connecting rods 29 may be also rigidly connectedtogether as by means of a rmgshaped bar 32 which passes outside of theconnecting rods 27 in order to reduce the length of the connecting rods.The connect.

. ranged near the rear edges of the cam drums.

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The pistons may be reciprocated by any elastic fluid but preferably formpart of an internal combustion engine of the two-,cycle type. ln thepresent instance, the cylinder is provided with axially-spaced sets ofintake` ports 35 and exhaust ports 36 which are respectively uncoveredby the pistons at the ends of their power strokes. The exhaust ports 36are connected with an exhaust pipe 37 which passes through a casingmember 38 surrounding the cylinder. A pre-compressed charge of acombustible mixture or air is introduced into the combustion chamberthrough the intake ports 35, 'which are connected by by-pass ports 39with pre-compression chambers at the opposite outer ends of thecylinder. Cylinder heads 40 are secured to the outer ends of thecylinder and each includes a suction-responsive intake valve 41 which,in the case of a carbureting engine, is connected to a carburetingdevice 42. ln the case of a fuel injection type of engine, thepre-compressed charge will consist of air. The combustible mixturepresent'in the combustion chamber may be ignited by a suitable ignitiondevice 43 or by means of the heat of compression.

The concentric shafts 11 and 13 are rotatable in opposite directions,and in order to insure such opposite rotation, especially on starting,it is desirable to provide some equalizing or synchronizing meansoperatively connected to the shafts. Such equalizing or synchronizingmeans may assume various forms and in the present instance is shown toconsist of a plurality of bevel pinions 44 meshing with bevel gears 45and 46 respectively secured to the outer and inner cam drums 17 and 18,the pinions being rotatably mounted on a ystationary carrier 47 whichincludes rearwardly projecting arms 48 passing through the space betweenthe drums and secured to some stationary part of the engine, such as theguide member 34.

In operation, the pistons 22and 23 are reciprocated in oppositedirections in the cylinder 21. In the movement of the pistons away fromeach other, a charge is compressed in the opposite outer end portions ofthe cylinders, and as soon as the intake ports 35 are uncovered by thepistons, the charge flows through the by-pass ports 39 and into thecombustion chamber between the pistons. This charge is compressed by thepistons on their inward strokes, and simultaneously fresh charges aredrawn into the pre-com pression chambers. At the end of the compressionstroke, the compressed charge beatrasos tween the now closely adjacentpistons is ignited, whereupon the pistons move outwardly in oppositedirections on power strokes, at the conclusion of which the spent gasesare discharged through the exhaust ports 36 and outwardly through theexhaust pipe 37. The fresh pre-compressed charge which is introducedthrough the ports 35 serves to scavenge the cylinder, and the cycle 0foperation is then repeated. The connecting rods 27 and 29, which arereciprocated by the pistons 22 and 23, effect the rotation of the camdrums 17 and 18 by the action of the rollers 28 and 30 on the side wallsof the cam grooves y19 and 20, thus rotating the pro pellers 15 and 16at the same speed but in opposite directions. rlhe rotation of thepropellers in the surrounding iuid medium serves to effect thepropulsion of the'craft on which the engine is mounted.

Since the engine is of the two-cycle type, the rollers 28 and 30 have atendency to remain in continuous engagement with the same sides of thecam grooves, thus minimizing lost motion. The reciprocating masses arepreferably balanced to minimize vibration, and the rotating masses arealso preferably balanced for the same reason and for the further purposeof minimizing gyroscopic effects. The side thrust on the roller-carryingends of the connecting rods is relatively low, since the lateralcomponent of pressure on one of the rollers will be substantiallybalanced out by an oppositely-directed lateral component of pressure onthe companion roller. The tooth pressures on the equ alizing pinions 44are relatively light since the load reactions on the twooppositely-rotating propellers are substantially the same. In someinstances, it may be necessary to make the propellers of di'erent lengthor pitch in order to divide the load equally between the two tandempropeller's. By the use of two oppositely-rotating propellers, thetorque on the engine casing, and consequently the torque on the craft onwhich the engine is mounted is cancelled out or minimized. Thedisposition of the power cylinder axially of the propeller shaftspermits the diameter 0f the engine casing to be materially reduced,thereby facilitating stream-lining either of the engine casing or of thesupport on which the engine is mounted.

What I claim as new and desire to secure by Letters Patent is:

1. In an engine, the combination of a pair of co-axial shafts rotatablein opposite directions, power means including a cylinder and a pistonrelatively reciprocatory therein, and

.cam means operatively connected with said "i power means for rotatingsaid coaxial shafts in opposite directions.

2. In an engine, the combination of a pair of co-axial shafts rotatablein opposite directions, a cam drum on each shaft each having lll asinuous cam surface, a cylinder arranged coaxially of said shaft, apiston 1n said cylinder, and means operatively connecting said pistonand the cam surfaces of both of Sald drums for rotating said shafts 1nopposite directions. f

3. in an engine, the combination of a pa1r of co-axial shaft-s rotatable1n opposite directions, cam drums on said respective shafts arranged oneWithin the other and each having a sinuous cam surface, a cylinderarranged 1n parallel relation to sald shaft, a reciprocatory pistonmounted 1n said cylinder, and means operatively connecting said pistonwith the cam surfaces of both of said cam drums for rotating said shaftsin opposite directions.

4.* ln an engine, the combination of a pair of co-axial shafts rotatablein opposite directions, a pair of cam drums respectively secured to saidshafts and each having a sinuons cam surface presenting a plurality ofpairs of crests, and power means including a reciprccatory piston havingan operative connection with the cam surfaces of said drums for rotatingsaid shafts at a speed which is snbmnltiple of the piston freqnency.

5. 'ln an engine, the combination' of a pair 6. In enmne the combinationof a )air y of co-a-Xial shafts rotatable in opposite directions, powermeans including a cylinder and a piston therein for rotating said shaftsat the same speed but in opposite directions, and synchronizing means.distinct from the power means for insuring the opposite rotation of saidshafts at the same speed.

7 In an engine, the combination of a rotatable shaft, a cylinderextending :5o-axially of said shaft, a pair of pistons mounted in saidcylinder for reciprocation in opposite directions, said cylinder andshaft heing arranged in tandem relation, a pair of actuating membersrespectively secured in said pistons and each projecting laterallytherefrom in opposite directions, and connecting rods secured to thelaterally projecting portions of said actuating members and havingoperative connections with said shaft at angularly spaced pointsthereof.

8. ln an engine, the combination of a pair of co-aXial shafts rotatablein opposite directions, a pair of cam drums respectively mounted on saidshafts and'each having a sinnous cam surface each presenting a pluralltyof pairs of crests, a cylinder arranged (zo-axially of said shafts, apair of pistons mounted in said cylinders for reciprocation in oppositedirections, a pair of actuating members for said respective pistonsprojecting laterally from said pistons at opposite sides thereof andarranged in different radial planes, a pair of connecting rods for eachpiston secured to the projecting portions of the actuating member andeach pair of connecting rods having an operative connection with the camsurface of the cam drum at diametrically opposite portions of said drum,the operative connections of one pair of said connecting rods with saidcam drum being angularly spaced from the operative connections of theother pair of connecting rods with said cam drum.

9. in an engine, the combination of a pair of co-aXial shafts rotatablein opposite directions, a power cylinder arranged in co-aXial relationto said shafts, a pair of opposed reciprocatory postons mounted in saidcylinder, and means operatively connecting said pistons and said rotaryshafts.

l0. In an engine, the combination of a pair of co-axial shafts rotatablein opposite directions; a power cylinder arranged in co-axial relationto said shafts, a pair of opposed reciprocatory pistons mounted in saidcylinder, and means operatively connecting each of said pistons withboth of said shafts for rotating said shafts in opposite directions.

11. ln an engine, the combination of a rotatable shaft, a cylinderarranged co-axially of said shaft, a pair of opposed pistons in saidcylinder, wrist pins for said pistons projecting'laterally from oppositesides thereof,

the wrist pin in one piston being disposed in a different plane from thewrist pin in the other piston, and pairs of connecting rods operativelyconnecting said wrist pins and said shaft and disposed in the respectiveplanes of said wrist pins.

12. ln an engine, the combination of a rotatable shaft, a cylinder'arranged co-axially of said shaft, apair of opposed pistons in saidcylinder, wrist pins for said pistons projecting laterally therefrom,the wrist pin in one piston being disposed in a diderent plane from thewrist pin in the otherpiston, and means operatively connecting saidwrist pins with said shaft.

in testimony whereof, l affix my signature.

ROYAL LEE.

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